This invention relates to a thermal transfer recording medium, more particularly to a heat-sensitive transfer recording medium having a uniform smooth surface with a stable coating and also giving good printing quality to both smooth paper and rough paper.
In a thermal transfer recording medium, for enhancing sensitivity (transferable at low energy) and making the system compact, the film thickness should be preferably thinner and it is desirable to provide only a colorant layer on the support by coating. However, for releasability, heat transferability, it is usual to provide a layer called peeling layer or adhesive layer composed mainly of a heat-fusible substance by coating between the colorant layer and the support.
On the other hand, also for formation of a colorant layer, for the purpose of avoiding fluctuation of the solid components in the coating solution, improving working environment, effecting cost down of production installation, etc., coating with an aqueous composition has become frequently used.
However, when an aqueous composition is coated on a layer composed mainly of waxes or strongly lipophilic heat-fusible substances, repellency, irregularity, pinholes, etc., are liable to be formed. This may be alleviated to some extent by adding a large amount of surfactants, but then there will ensue a drawback that printing performance becomes worsened.
Accordingly, it would be desirable to develop a technique which enables stable aqueous coating without lowering printing quality.